A driving assistance system is known that converts images of vehicle surroundings captured by plural imaging devices installed in a vehicle into bird's-eye view images, composites the bird's-eye view images to generate an output image, and presents the generated output image to an operator of the vehicle (See, e.g., Japanese Unexamined Patent Publication No. 2007-109166).
The disclosed driving assistance system generates an overlapping area image of an overlapping area of image capturing ranges of two cameras by setting a convoluted comb-like boundary line dividing the overlapping area image into two, and compositing the two bird's eye view images captured by the two cameras by alternately arranging the respective partial areas of the two bird's eye view images along the comb-like boundary.
Ordinarily, an object with a height that is located within the overlapping area is projected on two directions extending along the direction of two lines connecting the two cameras to the object. When the overlapping area is divided into two areas by one straight line and one bird's-eye view image captured by one of the cameras is used for one of the divided areas while the other bird's-eye view image captured by the other camera is used for the other divided area, the object may disappear from the overlapping area image.
In this regard, by compositing the images in the manner described above, the disclosed driving assistance system can prevent such an object with a height from disappearing from the overlapping area image and can facilitate recognition of the object by an operator.
The driving assistance system disclosed in Japanese Unexamined Patent Publication No. 2007-109166 uses a convoluted comb-like boundary line to composite two bird's eye view images by alternately arranging the respective partial areas of the two bird's eye view images to generate an output image. In a case where there is a wide discrepancy in the brightness of the two bird's eye view images, a noticeable comb-shaped light-dark pattern may be created, which results in the output image appearing unnatural to the operator viewing the output image.